JAFP-19-0064, Relief Request Associated with the Use of Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography for Ferritic and Austenitic Piping Welds

Relief Request Associated with the Use of Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography for Ferritic and Austenitic Piping Welds

ML19176A343
Person / Time
Site:	Calvert Cliffs, Dresden, Peach Bottom, Nine Mile Point, Byron, Braidwood, Limerick, Ginna, Clinton, Quad Cities, FitzPatrick, LaSalle
Issue date:	06/25/2019
From:	Jim Barstow Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
JAFP-19-0064, NMP1L3296, RS-19-068
Download: ML19176A343 (15)

Text

Exelon Generation 200 Exelon Way Kennett Square. PA 19348 www.exeloncorp.com 10 CFR 50.55a RS-19-068 JAFP-19-0064 NMP1L3296 June 25, 2019 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-72 and NPF-77 N RC Docket Nos. STN 50-456 and STN 50-457 Byron Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-37 and NPF-66 NRC Docket Nos. STN 50-454 and STN 50-455 Calvert Cliffs Nuclear Power Plant, Units 1 and 2 Renewed Facility Operating License Nos. DPR-53 and DPR-69 NRC Docket Nos. 50-317 and 50-318 Clinton Power Station, Unit 1 Facility Operating License No. NPF-62 NRC Docket No. 50-461 Dresden Nuclear Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-19 and DPR-25 NRC Docket Nos. 50-237 and 50-249 James A. FitzPatrick Nuclear Power Plant Renewed Facility Operating License No. DPR-59 NRG Docket No. 50-333 LaSalle County Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-11 and NPF-18 NRG Docket Nos. 50-373 and 50-374

Relief Request to Use Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography for Ferritic and Austenitic Piping Welds June 25, 2019 Page2 Limerick Generating Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-39 and NPF-85 NRC Docket Nos. 50-352 and 50-353 Nine Mile Point Nuclear Station, Units 1 and 2 Renewed Facility Operating License Nos. DPR-63 and NPF-69 NRC Docket Nos. 50-220 and 50-41 O Peach Bottom Atomic Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-44 and DPR-56 NRC Docket Nos. 50-277 and 50-278 Quad Cities Nuclear Power Station, Units 1 and 2 Renewed Facility Operating License Nos. DPR-29 and DPR-30 NRC Docket Nos. 50-254 and 50-265 R. E. Ginna Nuclear Power Plant Renewed Facility Operating License No. DPR-18 NRC Docket No. 50-244

Subject:

Relief Request Associated with the Use of Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography for Ferritic and Austenitic Piping Welds

Reference:

Letter from J. Barstow (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "Relief Request Associated with the Use of Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography for Ferritic and Austenitic Piping Welds," date February 15, 2019 In the Referenced letter, Exelon Generation Company, LLC (Exelon) requested a proposed alternative to the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, "Rules for lnservice Inspection of Nuclear Power Plant Components," on the basis that the proposed alternative provides an acceptable level of quality and safety. Specifically, this request was associated with the use of encoded phased array ultrasonic examination techniques in lieu of radiography for ferritic and austenitic piping welds.

Upon further review, it was identified that the RMS equation was incorrect. This error is being corrected by the ASME Code committee. This relief request is being resubmitted with the corrected RMS equation. Additionally, Three Mile Island Nuclear Station, Unit 1 is being deleted from this request. These changes are identified with revision bars.

There are no regulatory commitments in this letter.

Relief Request to Use Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography for Ferritic and Austenitic Piping Welds June 25, 2019 Page3 If you have any questions concerning this letter, please contact Tom Loomis at (610) 765-5510.

Respectfully, James Barstow Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Attachment:

Relief Request Associated with the Use of Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography for Ferritic and Austenitic Piping Welds cc: Regional Administrator - NRG Region I Regional Administrator - NRG Region Ill NRG Senior Resident Inspector - Braidwood Station NRG Senior Resident Inspector - Byron Station NRG Senior Resident Inspector - Calvert Cliffs Nuclear Power Plant NRG Senior Resident Inspector - Clinton Power Station NRG Senior Resident Inspector - Dresden Nuclear Power Station NRG Senior Resident Inspector - James A. FitzPatrick Nuclear Power Plant NRG Senior Resident Inspector - LaSalle County Station NRG Senior Resident Inspector - Limerick Generating Station NRG Senior Resident Inspector - Nine Mile Point Nuclear Station NRG Senior Resident Inspector - Peach Bottom Atomic Power Station NRG Senior Resident Inspector - Quad Cities Nuclear Power Station NRG Senior Resident Inspector - R.E. Ginna Nuclear Power Plant NRG Project Manager - Braidwood Station NRG Project Manager - Byron Station NRG Project Manager - Calvert Cliffs Nuclear Power Plant NRG Project Manager - Clinton Power Station NRG Project Manager - Dresden Nuclear Power Station NRG Project Manager - James A. FitzPatrick Nuclear Power Plant NRG Project Manager - LaSalle County Station NRG Project Manager - Limerick Generating Station NRG Project Manager - Nine Mile Point Nuclear Station NRG Project Manager - Peach Bottom Atomic Power Station NRG Project Manager - Quad Cities Nuclear Power Station NRG Project Manager - R.E. Ginna Nuclear Power Plant Illinois Emergency Management Agency - Division of Nuclear Safety R. R. Janati, Commonwealth of Pennsylvania D. A. Tancabel, State of Maryland A. L. Peterson, NYSERDA B. Frymire, NYSPSC

Attachment Relief Request Associated with the Use of Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography for Ferritic and Austenitic Piping Welds

10 CFR 50.55a RELIEF REQUEST Revision 0 (Page 1 of 11)

Request for Relief for Use of Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography in Accordance with 10 CFR 50.55a(z)(l)

--Alternative Provides Acceptable Level of Quality or Safety--

1. ASME Code Component(s) Affected All American Society of Mechanical Engineers (ASME), Boiler & Pressure Vessel (BPV) Code,Section XI, ISi ferritic and austenitic piping welds requiring radiography during repair/replacement activities.

2. Applicable Code Edition and Addenda PLANT INTERVAL EDITION START END Braidwood Station, Units Fourth 2013 Edition August29,2018 July 28, 2028 1and2 November 5, 2018 October 16, 2028 Byron Station, Units Fourth 2007 Edition, through 2008 July 16, 2016 July 15, 2025 1and2 Addenda Calvert Cliffs Nuclear Fourth 2013 Edition July 1, 2019 June 30, 2029 Power Plant, Units 1 and 2

Clinton Power Station, Third 2004 Edition July 1, 2010 June 30, 2020 Unit 1 Clinton Power Station, Fourth 2013 Edition July 1, 2020 June 30, 2030 Unit 1 Dresden Nuclear Power Fifth 2007 Edition, through 2008 January 20, 2013 January 19, 2023 Station, Units 2 and 3 Addenda James A. FitzPatrick Fifth 2007 Edition, through 2008 August 1, 2017 June 15, 2027 Nuclear Power Plant Addenda LaSalle County Stations, Fourth 2007 Edition, through 2008 October 1, 2017 September 30, 2027 Units 1 and 2 Addenda Limerick Generating Fourth 2007 Edition, through 2008 February 1, 2017 January 31, 2027 Station, Units 1 and 2 Addenda Nine Mile Point Nuclear Fourth 2004 Edition August23,2009 August22,2019 Station, Unit 1 Nine Mile Point Nuclear Fifth 2013 Edition August23,2019 August 22, 2029 Station, Unit 1 Nine Mile Point Nuclear Fourth 2013 Edition October 6, 2018 August22,2028 Station, Unit 2 Peach Bottom Atomic Fifth 2013 Edition January 1, 2019 December 31, 2028 Power Station, Units 2 and 3

10 CFR 50.SSa RELIEF REQUEST Revision 0 (Page 2 of 11)

PLANT INTERVAL EDITION START END Quad Cities Nuclear Fifth 2007 Edition, through 2008 April 2, 2013 April 1, 2023 Power Station, Units 1 Addenda and 2 R. E. Ginna Nuclear Fifth 2004 Edition January 1, 2010 December 31, 2019 Power Plant R. E. Ginna Nuclear Sixth 2013 Edition January 1, 2020 December 31, 2029 Power Plant

3. Applicable Code Requirement IW A-4221 requires that items used for repair/replacement activities meet the applicable Owner's Requirements and Construction Code requirements when performing repair/replacement activities. IW A-4520 requires that welded joints made for installation of items be examined in accordance with the Construction Code identified in the Repair/Replacement Plan.

4. Reason for Request Replacement of piping is periodically performed in support of the Flow Accelerated Corrosion (FAC) program as well as other repair and replacement activities. The use of encoded Phased Array Ultrasonic Examination Techniques (PAUT) in lieu of radiography (RT) to perform the required examinations of the replaced welds would eliminate the safety risk associated with performing RT, which includes the planned exposure and the potential for accidental personnel exposure to plant workers. PAUT also minimizes the impact on other outage activities normally involved with performing RT such as limited access to work. In addition, encoded PAUT is equivalent or superior to the code-required RT examination for ASME ferritic and austenitic piping repair/replacement welds for detecting and sizing critical (planar) flaws, such as cracks and lack of fusion. PAUT provides sizing capabilities for both depth and length dimensions of the flaw, which are required to apply the acceptance criteria of the applicable code case. RT does not provide depth sizing capabilities.

Exelon Generation Company, LLC (Exelon) requests approval of this proposed alternative for the remainder of the intervals identified in Section 2 above.

5. Proposed Alternative and Basis for Use The use of encoded PAUT is proposed in lieu of the Code-required RT examination for ASME ferritic and austenitic piping repair/replacement welds. Similar techniques are being used throughout the nuclear industry for examination of dissimilar metal welds and overlaid welds, as well as other applications including ASME B31.1 piping replacements.

This proposed alternative request includes requirements that provide an acceptable level of quality and safety that satisfy the requirements of 10 CFR 50.55a(z)(l). The capability

10 CFR 50.SSa RELIEF REQUEST Revision 0 (Page 3 of 11) of the alternative technique is comparable to the examination methods documented in the ASME Code Sections Ill, VIII and IX, and associated code cases (8.1, 8.3, 8.5, 8.6, 8.8, 8.9, 8.10, 8.11, 8.12, 8.13 and 8.14) using ultrasonic examination techniques for weld acceptance. The examinations will be performed using personnel and procedures qualified with the requirements of Section 5 .1 below.

5.1 Proposed Alternative (1) Use of this alternative request is limited to welds made as part of a repair/replacement activity and is subject to review by the Authorized Inspection Agency.

(2) The welds to be examined shall be conditioned such that transducers properly couple with the scanning surface with no more than a 1/32 in. (0.8 mm) gap between the search unit and the scanning surface.

(3) The ultrasonic examination shall be performed with equipment, procedures, and personnel qualified by performance demonstration as described below.

(4) The examination volume shall include 100% of the weld volume and the weld-to-base-metal interface.

(a) Angle beam examination of the complete examination volume for fabrication flaws oriented parallel to the weld joint shall be performed.

(b) Angle beam examination for fabrication flaws oriented transverse to the weld joint shall be performed to the extent practical. Scan restrictions that limit complete coverage shall be documented.

(c) A supplemental straight beam examination shall be performed on the volume of base metal through which the angle beams will travel to locate any reflectors that can limit the ability of the angle beam to examine the weld.

Detected reflectors that may limit the angle beam examination shall be recorded and evaluated for impact on examination coverage. The straight beam examination procedure, or the straight beam portion of the procedure, is required to be qualified in accordance with ASME Section V, Article 4.

(5) All detected flaw indications from (4)(a) and (4)(b) above shall be considered planar flaws and compared to the preservice acceptance standards for volumetric examination in accordance with IWB-3000, IWC-3000 or IWD-3000, as applicable.

Analytical evaluation for acceptance of flaws in accordance with IWB-3600, IWC-3600 or IWD-3600 is permitted for flaws that exceed the applicable acceptance standards and are confirmed by surface or volumetric examination to be non-surface connected.

(6) Flaws exceeding the applicable acceptance standards and when analytical evaluation has not been performed for acceptance, shall be reduced to an acceptable size or

10 CFR 50.55a RELIEF REQUEST Revision 0 (Page 4 of 11) removed and repaired, and the location of the repair shall be reexamined using the same ultrasonic examination procedure that detected the flaw.

(7) The ultrasonic examination shall be performed using encoded UT technology that produces an electronic record of the ultrasonic responses indexed to the probe position, permitting off-line analysis of images built from the combined data. Where component configuration does not allow for effective examination for transverse flaws, (e.g., pipe-to-valve, tapered weld transition, weld shrinkage, etc.) the use of non-encoded UT technology may be used for transverse flaws. The basis for the non-encoded examination shall be documented.

(8) A written ultrasonic examination procedure qualified by performance demonstration shall be used. The qualification shall be applicable to the scope of the procedure, e.g.,

flaw detection or sizing (length or through-wall height), encoded or non-encoded, single or dual side access. The procedure shall:

(a) contain a statement of scope that specifically defines the limits of procedure applicability (e.g., minimum and maximum thickness, minimum and maximum diameter, scanning access);

(b) specify which parameters are considered essential variables, and a single value, a range of values or criteria for selecting each of the essential variables; (c) list the examination equipment, including manufacturer and model or series; (d) define the scanning requirements; such as beam angles, scan patterns, beam direction, maximum scan speed, extent of scanning, and access; (e) contain a description of the calibration method (i.e., actions required to ensure that the sensitivity and accuracy of the signal amplitude and time outputs of the examination system, whether displayed, recorded, or automatically processed, are repeated from examination to examination);

(f) describe the method and criteria for discrimination of indications (e.g.,

geometric indications versus indications of flaws and surface versus subsurface indications); and (g) describe the surface preparation requirements.

(9) Performance demonstration specimens shall conform to the following requirements:

(a) The specimens shall be fabricated from ferritic or austenitic material, similar to the material being examined. Ferritic specimens shall be fabricated with the same inside surface cladding process, if applicable, with the following exceptions:

10 CFR 50.SSa RELIEF REQUEST Revision 0 (Page 5 of 11)

(i) Demonstration with shielded metal arc weld (SMAW) single-wire cladding is transferable to multiple-wire or strip-clad processes; (ii) Demonstration with multiple-wire or strip-clad process is considered equivalent but is not transferable to SMAW type cladding processes.

(b) The demonstration specimens shall contain a weld representative of the joint to be ultrasonically examined, including the same welding processes.

(c) The demonstration set shall include specimens not thicker than 0.1 in. (2.5 mm) more than the minimum thickness, nor thinner than 0.5 in. (13 mm) less than the maximum thickness for which the examination procedure is applicable. The demonstration set shall include the minimum, within Y2 inch of the nominal of the nominal outside diameter (OD), and maximum pipe diameters for which the examination procedure is applicable. If the procedure is applicable to piping of 24 in. (600 mm) OD or larger, the specimen set must include at least one specimen 24 in. O.D. (600 mm) or larger but need not include the maximum diameter.

(d) The demonstration specimen scanning and weld surfaces shall be representative of the surfaces to be examined.

(e) The demonstration specimen set shall include geometric conditions that require discrimination from flaws (e.g., counterbore, weld root conditions, or weld crowns) and limited scanning surface conditions for single-side access, when applicable.

(f) The demonstration specimens shall include both planar and volumetric fabrication flaws (e.g., lack of fusion, crack, incomplete penetration, slag inclusions) representative of the welding process or processes of the welds to be examined. The flaws shall be distributed throughout the examination volume.

(g) Specimens shall be divided into flawed and unflawed grading units as follows:

(i) Flawed grading units shall be the actual flaw length, plus a minimum of 0.25 in. (6 mm) on each end of the flaw. Unflawed grading units shall be at least 1 in. (25 mm);

(ii) The number of unflawed grading units shall be at least 1-112 times the number of flawed grading units.

(h) Demonstration specimen set flaw distribution shall be as follows:

(i) For thickness greater than 0.50 in. (13 mm); at least 20% of the flaws shall be distributed in the outer third of the specimen wall thickness, at least

10 CFR 50.55a RELIEF REQUEST Revision 0 (Page 6 of 11) 20% of the flaws shall be distributed in the middle third of the specimen wall thickness and at least 40% of the flaws shall be distributed in the inner third of the specimen wall thickness. For thickness 0.50 in. (13 mm) and less, at least 20% of the flaws shall be distributed in the outer half of the specimen wall thickness and at least 40% of the flaws shall be distributed in the inner half of the specimen wall thickness.

(ii) At least 30% of the flaws shall be classified as surface planar flaws in accordance with IW A-3310. At least 40% of the flaws shall be classified as subsurface planar flaws in accordance with IW A-3320.

(iii) At least 50% of the flaws shall be planar flaws, such as lack of fusion, incomplete penetration, or cracks. At least 20% of the flaws shall be volumetric flaws, such as slag inclusions.

(iv) The flaw through-wall heights shall be based on the applicable acceptance standards for volumetric examination in accordance with IWB-3400, IWC-3400 or IWD-3000, as applicable. At least 30% of the flaws shall be classified as acceptable planar flaws, with the smallest flaws being at least 50% of the maximum allowable size based on the applicable all aspect ratio for the flaw. Additional smaller flaws may be included in the specimens to assist in establishing a detection threshold, but shall not be counted as a missed detection if not detected. At least 30% of the flaws shall be classified as unacceptable in accordance with the applicable acceptance standards. Welding fabrication flaws are typically confined to a height of a single weld pass. Flaw through-wall height distribution shall range from approximately one to four weld pass thicknesses, based on the welding process used.

(v) If applicable, at least two flaws, but no more than 30% of the flaws, shall be oriented perpendicular to the weld fusion line and the remaining flaws shall be circumferentially oriented.

(vi) For demonstration of single-side-access capabilities, at least 30% of the flaws shall be located on the far side of the weld centerline and at least 30% of the planar flaws shall be located on the near side of the weld centerline. The remaining flaws shall be distributed on either side of the weld.

( 10) Ultrasonic examination procedures shall be qualified by performance demonstration in accordance with the following requirements.

(a) The procedure shall be demonstrated using either a blind or a non-blind demonstration.

10 CFR 50.55a RELIEF REQUEST Revision 0 (Page 7 of 11)

(b) The non-blind performance demonstration is used to assist in optimizing the examination procedure. When applying the non-blind performance demonstration process, personnel have access to limited knowledge of specimen flaw information during the demonstration process. The non-blind performance demonstration process consists of an initial demonstration without any flaw information, an assessment of the results and feedback on the performance provided to the qualifying candidate. After an assessment of the initial demonstration results, limited flaw information may be shared with the candidate as part of the feedback process to assist in enhancing the examination procedure to improve the procedure performance. In order to maintain the integrity of the specimens for blind personnel demonstrations, only generalities of the flaw information may be provided to the candidate.

Procedure modifications or enhancements made to the procedure, based on the feedback process, shall be applied to all applicable specimens based on the scope of the changes.

(c) Objective evidence of a flaw's detection, length and through-wall height sizing, in accordance with the procedure requirements, shall be provided to the organization administering the performance demonstration.

(d) The procedure demonstration specimen set shall be representative of the procedure scope and limitations (e.g., thickness range, diameter range, material, access, surface condition).

(e) The demonstration set shall include specimens to represent the minimum and maximum diameter and thickness covered by the procedure. If the procedure spans a range of diameters and thicknesses, additional specimens shall be included in the set to demonstrate the effectiveness of the procedure throughout the entire range.

(f) The procedure demonstration specimen set shall include at least 30 flaws and shall meet the requirements of (9) above.

(g) Procedure performance demonstration acceptance criteria (i) To be qualified for flaw detection, all flaws in the demonstration set that are not less than 50% of the maximum allowable size, based on the applicable all aspect ratio for the flaw, shall be detected. In addition, when performing blind procedure demonstrations, no more than 20% of the non-flawed grading units may contain a false call. Any non-flaw condition (e.g., geometry) reported as a flaw shall be considered a false call.

(ii) To be qualified for flaw length sizing, the root mean square (RMS) error of the flaw lengths estimated by ultrasonics, as compared with the true

10 CFR 50.55a RELIEF REQUEST Revision 0 (Page 8 of 11) lengths, shall not exceed 0.25 in. (6 mm) for diameters of NPS 6.0 in.

(DN150) and smaller, and 0.75 in. (18 mm) for diameters greater than NPS 6.0 in. (DN150).

(iii) To be qualified for flaw through-wall height sizing, the RMS error of the flaw through-wall heights estimated by ultrasonics, as compared with the true through-wall heights, shall not exceed 0.125 in. (3 mm).

(iv) RMS error shall be calculated as follows:

.f. (m; _ t;) 2]1/2 HMS = ~1 -=~

1 ---

[ n where:

mi = measured flaw size n = number of flaws measured ti = true flaw size (h) Essential variables may be changed during successive personnel performance demonstrations. Each examiner need not demonstrate qualification over the entire range of every essential variable.

(i) Expansion of a procedure, demonstrated in accordance with ( 10), to include an additional material type (i.e. ferritic or austenitic) shall meet the following:

(i) The procedure expansion may be performed during successive personnel performance demonstrations, performed with (1 l)(a), with the exception that all flaws must be detected.

(ii) The examination technique is the same, e.g. wave modes, angles, V-path, access, etc. Any changes to the examination technique shall be performed in accordance with (10).

(iii) The demonstration set must include the minimum and maximum diameter and thickness range of the new material being demonstrated.

(iv) Personnel using the expanded procedure shall demonstrate the additional material type in accordance with ( 11 ).

(11) Ultrasonic examination personnel shall be qualified in accordance with IW A-2300.

In addition, examination personnel shall demonstrate their capability to detect and size flaws by performance demonstration using the qualified procedure in accordance with the following requirements:

10 CFR 50.SSa RELIEF REQUEST Revision 0 (Page 9 of 11)

(a) The personnel performance demonstration shall be conducted in a blind fashion (flaw information is not provided).

(b) The demonstration specimen set shall contain at least 10 flaws and shall meet the flaw distribution requirements of (9)(h) above, with the exception of (9)(h)(v). When applicable, at least one flaw, but no more than 20% of the flaws, shall be oriented perpendicular to the weld fusion line and the remaining flaws shall be circumferentially oriented.

(c) Personnel performance demonstration acceptance criteria:

(i) To be qualified for flaw detection, at least 80% of the flaws in the demonstration set shall be detected and no more than 20% of the grading units shall contain a false call. Any non-flaw condition (e.g., geometry) reported as a flaw shall be considered a false call.

(ii) To be qualified for flaw length sizing, the RMS error of the flaw lengths estimated by ultrasonics, as compared with the true lengths, shall not exceed 0.25 in. (6 mm) for NPS 6.0 in. (DN150) and smaller, and 0.75 in.

(18 mm) for diameters larger than NPS 6.0 in. (DN150).

(iii) To be qualified for flaw through-wall height sizing, the RMS error of the flaw through-wall heights estimated by ultrasonics, as compared with the true through-wall heights, shall not exceed 0.125 in. (3 mm).

(12) Exelon Generation is responsible for reviewing the procedure and demonstration results to validate that the ranges of the essential variables in the procedure were included in the demonstration.

(13) Documentation of the qualifications of procedures and personnel shall be maintained. Documentation shall include identification of personnel, NDE procedures, equipment and specimens used during qualification, and results of the performance demonstration.

5.2 Basis for use The basis for this proposed alternative is that encoded PAUT is equivalent or superior to RT for detecting and sizing critical (planar) flaws. In this regard, the basis for the proposed alternative was developed from numerous codes, code cases, associated industry experience, articles, and the results of RT and encoded PAUT examinations.

The examination procedure and personnel performing examinations are qualified using representative piping conditions and flaws that demonstrate the ability to detect and size flaws that are both acceptable and unacceptable to the defined acceptance standards. The demonstrated ability of the examination procedure and personnel to appropriately detect and size flaws provides an acceptable level of quality and safety alternative as allowed by 10 CFR 50.55a(z)(l).

10 CFR 50.SSa RELIEF REQUEST Revision 0 (Page 10 of 11)

6. Duration of Proposed Alternative Relief is requested for the remainder of the interval for the plants specified in Section 2 above.

7. Precedents Letter from J. Danna (U.S. Nuclear Regulatory Commission) to D. Stoddard (Dominion Energy Nuclear Connecticut, Inc.), "Millstone Power Station, Unit Nos. 2 and 3 -

Alternative Requests RR-04-27 AND IR-3-38 for the Use of Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography (EPID L-2018-LLR-001 l),"

dated September 17, 2018 (ML18252A003).

8. References

1. ASME Section III Code Case N-659-2, "Use of Ultrasonic Examination in Lieu of Radiography for Weld Examination Section III, Division l;Section III, Division 3,"

dated June 9, 2008.

2. Pacific Northwest National Laboratory Report PNNL-19086, "Replacement of Radiography with Ultrasonics for the Nondestructive Inspection of Welds -

Evaluation of Technical Gaps - An Interim Report," dated April 2010.

3. ASME B31.l, Case 168, "Use of Ultrasonic Examination in Lieu of Radiography for B3 l. l Application," dated June 1997.

4. ASME Sections III and XI.

5. ASME Section ill, Code Case N-818, "Use of Analytical Evaluation approach for Acceptance of Full Penetration Butt Welds in Lieu of Weld Repair," dated December 6, 2011.

6. ASME Code Case 2235-9, 2005; "Use of Ultrasonic Examination in Lieu of Radiography Section I,Section VIII, Divisions 1 and 2, and Section XII," dated October 11, 2005.

7. Journal of Pressure Vessel Technology, "Technical Basis for ASME Section VIII Code Case 2235 on Ultrasonic Examination of Welds in Lieu of Radiography;" Rana, Hedden, Cowfer and Boyce, Volume 123 dated August 2001.

8. ASME Code Case 2326, "Ultrasonic Examination in Lieu of Radiographic Examination for Welder Qualification Test CouponsSection IX," dated January 20, 2000.

9. ASME Code Case 2541, "Use of Manual Phased Array Ultrasonic Examination Section V," dated January 19, 2006.

10 CFR 50.55a RELIEF REQUEST Revision 0 (Page 11 of 11)

10. ASME Code Case 2558, "Use of Manual Phased Array E-Scan Ultrasonic Examination Per Article 4 Section V," dated December 30, 2006.

11. ASME Code Case 2599, "Use of Linear Phased Array E-Scan Ultrasonic Examination per Article 4 Section V," dated January 29, 2008.

12. ASME Code Case 2600, "Use of Linear Phased Array S-Scan Ultrasonic Examination per Article 4 Section V," dated January 9, 2008.

13. ASME Section XI, Code Case N-713, "Ultrasonic Examination in Lieu of Radiography," dated November 10, 2008.

14. ASME Section XI, Code Case N-831, "Ultrasonic Examination in Lieu of Radiography for Welds in Ferritic Pipe," dated October 20, 2016.

15. US NRC, NUREG/CR-7204, "Applying Ultrasonic Testing in Lieu of Radiography for Volumetric Examination of Carbon Steel Piping" (ML5253A674).

16. Technical Basis for Substituting Ultrasonic Testing for Radiographic Testing for New, Repaired, and Replacement Welds for ASME Section XI, Division 1, Stainless Steel Piping. EPRI, Palo Alto, CA; 2017. 3002010297.